(57) The application relates to a process for the preparation of alkylated aromatic hydrocarbons by isomerisation of a normal alpha-olefin having preferably 20 to 28 carbon atoms in the presence of a first acidic catalyst which can be a molecular sieve with a one-dimensional pore system; the isomerised olefin is then used as alkylating agent for a non-oxygen-containing aromatic hydrocarbon such as benzene, toluene, xylene or cumene, in the pressence of a second acidic catalyst selected from the group consisting natural zeolites, synthetic zeolites and clays, preferably zeolite Y.
The prepared compound, which forms a further aspect of the invention, has less than 40 wt.% of components characterised by having 2-aryl attachment, at least 20 wt.% (preferably at least 75 wt.%) monoalkylate, and not more than 80% of the alkyl groups are branched.